#include "key.h"

uchar key_scan_bkd() {
	uchar temp = 0;
	
	P44 = 0; P42 = 1; P35 = 1; P34 = 1;
	if(P33 == 0) temp = 4;
	if(P32 == 0) temp = 5;
	if(P31 == 0) temp = 6;
	if(P30 == 0) temp = 7;
	
	P44 = 1; P42 = 0; P35 = 1; P34 = 1;
	if(P33 == 0) temp = 8;
	if(P32 == 0) temp = 9;
	if(P31 == 0) temp = 10;
	if(P30 == 0) temp = 11;
	if(P33 == 0 && P32 == 0) temp = 89;
	
	P44 = 1; P42 = 1; P35 = 0; P34 = 1;
	if(P33 == 0) temp = 12;
	if(P32 == 0) temp = 13;
	if(P31 == 0) temp = 14;
	if(P30 == 0) temp = 15;
	
	P44 = 1; P42 = 1; P35 = 1; P34 = 0;
	if(P33 == 0) temp = 16;
	if(P32 == 0) temp = 17;
	if(P31 == 0) temp = 18;
	if(P30 == 0) temp = 19;
	
	P3 = 0xFF;
	
	return temp;

}
